6 fast facts about flash floods in Central Texas

By J.M. Scott

on June 1, 2016 1:37 PM

The Texas hill country is the most flash flood-prone region in the United States, according to the National Weather Service. Click ahead for 6 fast facts on why the area is known as "Flash Flood Alley."

The Texas hill country is the most flash flood-prone region in the United States, according to the National Weather Service. Click ahead for 6 fast facts on why the area is known as "Flash Flood Alley."

Photo: Kin Man Hui

The Texas hill country is the most flash flood-prone region in the...photo-10173657.130374 - |ucfirst

1. A flash flood occurs when an excessive amount of rain falls in a short amount of time, causing to creeks and rivers to rapidly rise.

Flash floods generally occur within six hours of when a storm hits. When eight to 15 inches of rain fall in a few hours, rivers can rise 11 to 15 feet.

Source: Texas Department of Public Safety, National Sever Storms Laboratory

Texas has two rainy seasons. April and May are the wettest months with spring thunderstorms that form in the northwest, over the Balcones Escarpment. Tropical storms from the Gulf of Mexico make September and October the second wettest rainy season in Texas. While tropical storms also lead to floods, they are different from those of "Flash Flood Alley."

2. Flash floods occur the most in spring. Texas has two rainy...photo-9821258.130374 - |ucfirst

3. The Balcones Escarpment is a geological formation that makes the Hill Country and its evil twin "Flash Flood Alley."

Extending from Del Rio to Dallas, the Balcones Escarpment is the range of cliffs that drops from the Edwards Plateau to the Balcones Fault line and leads to the Coastal Plains in the southeast. Large thunderstorms form and stall along the uplift, hovering over the Hill Country.

4. Rain water funnels down from the hills into rivers, streams and creeks.

Steep and narrow valleys allow for surging waters to rise rapidly; a shallow creek can swell to 10 feet in less than an hour.

4. Rain water funnels down from the hills into rivers, streams and creeks.

Steep and narrow valleys allow for surging waters to rise rapidly; a shallow creek can swell to 10 feet in less than an hour.

Photo: Pedernales Falls State Park

4. Rain water funnels down from the hills into rivers, streams...photo-10150818.130374 - |ucfirst

5. The rocky terrain of the Hill Country exacerbates flash flood development.

There is less soft soil to soak up rainwater.

5. The rocky terrain of the Hill Country exacerbates flash flood development.

There is less soft soil to soak up rainwater.

Photo: Courtesy Photo /Texas Parks And Wildlife

5. The rocky terrain of the Hill Country exacerbates flash flood...photo-10054471.130374 - |ucfirst

6. Year after year, Texas leads the nation in flood-related deaths.

Almost mirroring the Interstate 35 corridor, "flash flood alley" runs through the middle of some of the busiest cities and most popular towns in Texas. About 50% of flood fatalities occur in a flash flood, and 75% of flood-related deaths in Texas occur in vehicles.

The Texas hill country is the most flash flood-prone region in the United States, according to the National Weather Service. Click ahead for 6 fast facts on why the area is known as "Flash Flood Alley."

The Texas hill country is the most flash flood-prone region in the United States, according to the National Weather Service. Click ahead for 6 fast facts on why the area is known as "Flash Flood Alley."